#include <cstdio>

const int N = 1000005;
int n, m, q, v1, v2, score, need, ans;
char s[N];

int main() {
#ifndef ONLINE_JUDGE
#ifdef LOCAL
  freopen("testdata.in", "r", stdin);
  freopen("testdata.out", "w", stdout);
#else
  freopen("choice.in", "r", stdin);
  freopen("choice.out", "w", stdout);
#endif
#endif

  scanf("%d%d%d%d%d", &q, &n, &m, &v1, &v2);
  scanf("%s", s + 1);
  for (int i = 1; i <= q; ++i) { score += s[i] == '+' ? 1 : -1; }
  printf("%d", (score + n - m) * v1 / 2);
  return 0;
}